Blasts from high explosive detonations are endemic in military combat. They are characterized by a rapidly moving pressure/shock wave (often exceeding ˜330 meters per second in air) with a blast overpressure (i.e. magnitude of the moving pressure wave measured as a pressure difference Δp over and above a normal atmospheric/ambient pressure) which can be several atmospheres greater than ambient pressure. If blast overpressure exceeds certain pressure or duration thresholds, such blasts can cause neuro-psychological or physiological injury or death to exposed soldiers and civilians. In particular, blast-induced traumatic brain injury (“biTBI”) can result from mechanical loads in the brain, often without skull fracture, which can cause complex, long lasting symptoms.
Diagnosis of biTBI is problematic because precise biological damage thresholds are not currently known, and blast exposure is affected significantly by a blast victim's (e.g. soldier's) local environment. For example, blast exposure in an unconfined space is much less severe than in an enclosed space, or near a wall or interior corner, and can also differ from conditions inside a vehicle. Consequently, it is difficult to determine the severity of the blast wave to which a blast victim has been exposed. This makes determination of biological damage thresholds from field injury data challenging. And even if these thresholds were known, they cannot be used to diagnose biTBI unless the exact blast conditions experienced by a particular individual can be measured. The objective determination of the severity of blast effects requires assessment during the exposure.
Objective determination of how large a blast a victim had been exposed to would be valuable to combat medics or other first responders attempting to render aid to the victim on the battlefield, and also to doctors and other professionals responsible for the medium and long term care of the victim. Furthermore, improved measurement of blast exposure would allow more rapid and accurate diagnosis of blast-related injuries (i.e. injury symptoms to be better correlated with mechanical insult) and could potentially lead to improved treatment techniques for blast victims or the design of improved protective armor or equipment.